fix: do not interrupt IMAP loop from get_connectivity_html()

Android calls get_connectivity_html()
every time connectivity changes, which in turn interrupts
IMAP loop and triggers change from "not connected" to "connecting"
state.

To avoid such infinite loop of IMAP interrupts when
there is not connectivity, update quota only when IMAP
loop is interrupted otherwise. This anyway happens
when a message is received or maybe_network is called.

Also remove outdated comments about `Action::UpdateRecentQuota` job
which does not exist anymore.

src/context.rs

@@ -211,9 +211,6 @@ pub struct InnerContext {
     /// Set to `None` if quota was never tried to load.
     pub(crate) quota: RwLock<Option<QuotaInfo>>,
 
-    /// Set to true if quota update is requested.
-    pub(crate) quota_update_request: AtomicBool,
-
     /// IMAP UID resync request.
     pub(crate) resync_request: AtomicBool,
 
@@ -384,7 +381,6 @@ impl Context {
             scheduler: SchedulerState::new(),
             ratelimit: RwLock::new(Ratelimit::new(Duration::new(60, 0), 6.0)), // Allow at least 1 message every 10 seconds + a burst of 6.
             quota: RwLock::new(None),
-            quota_update_request: AtomicBool::new(false),
             resync_request: AtomicBool::new(false),
             new_msgs_notify,
             server_id: RwLock::new(None),